Using (what goes in here) for sub routine
 

Was reading the Excel Help on the Sub Statement and this is the example that
is shown:
' Sub procedure definition.
' Sub procedure with two arguments.
Sub SubComputeArea(Length, TheWidth)
Dim Area As Double ' Declare local variable.
If Length = 0 Or TheWidth = 0 Then
' If either argument = 0.
Exit Sub ' Exit Sub immediately.
End If
Area = Length * TheWidth ' Calculate area of rectangle.
Debug.Print Area ' Print Area to Debug window.
End Sub

I notice that the there is Lenght and TheWidth in the brackets after the sub
name. Am I correct in assuming that these have to be given values
somewhere? I notice in the sub routine they are not defined so I am
assuming they are definned elsewhere. I am trying to learn about the
arguments that can go in that set of brackets after the sub name to further
my knowledge. I see things like Sub Name(ByVal etc...) and was trying to
figure out the whens and whys of using that and where is that stuff defined
as I cannot find it in the help when I do a search for ByVal etc....

Thanks in Advance and have a Happy New Year everyone

Wally Steadman

Using (what goes in here) for sub routine
 

It is defined in the help for SUB

Sum Main()
Dim dbllLen as double, dblWidth as double
dblLen = 6
dblWidth = 8
SubComputeArea dblLen, dblWidth
End Sub

Sub SubComputeArea(Length, TheWidth)
Dim Area As Double ' Declare local variable.
If Length = 0 Or TheWidth = 0 Then
' If either argument = 0.
Exit Sub ' Exit Sub immediately.
End If
Area = Length * TheWidth ' Calculate area of rectangle.
Debug.Print Area ' Print Area to Debug window.
End Sub

If you know you are going to pass variables defined as double you can do

Sub SubComputeArea(Length as double, TheWidth as double)

Length and TheWidth are declared along with the Sub in the sub declaration
(the line above)

They are place holders for the variables actually passed to the sub.

by default they are passes a references so if the sub does anything to the
passed variables the values held by those variables is changed (you can
explicitly do

Sub SubComputeArea(byRef Length as double, byRef TheWidth as double)

If you use ByVal, then the value held be the variables are passed and the
function uses the placeholder variables (so to speak) to hold the passed
values and those placeholder/dummy variables are manipulated in teh sub.
Unlike the byRef variables, the original variable values are not affected by
actions performed in the sub.

--
Regards,
Tom Ogilvy


"Wally Steadman" wrote in message
...
Was reading the Excel Help on the Sub Statement and this is the example
that
is shown:
' Sub procedure definition.
' Sub procedure with two arguments.
Sub SubComputeArea(Length, TheWidth)
Dim Area As Double ' Declare local variable.
If Length = 0 Or TheWidth = 0 Then
' If either argument = 0.
Exit Sub ' Exit Sub immediately.
End If
Area = Length * TheWidth ' Calculate area of rectangle.
Debug.Print Area ' Print Area to Debug window.
End Sub

I notice that the there is Lenght and TheWidth in the brackets after the
sub
name. Am I correct in assuming that these have to be given values
somewhere? I notice in the sub routine they are not defined so I am
assuming they are definned elsewhere. I am trying to learn about the
arguments that can go in that set of brackets after the sub name to
further
my knowledge. I see things like Sub Name(ByVal etc...) and was trying to
figure out the whens and whys of using that and where is that stuff
defined
as I cannot find it in the help when I do a search for ByVal etc....

Thanks in Advance and have a Happy New Year everyone

Wally Steadman

Using (what goes in here) for sub routine
 

ByVal literaly passes a copy of the variable instead of the variable itself.
As such there is some overhead involved in pass ByVal as a copy has to be
made. That having been said unless I need to modify the value of the incoming
variable I alway use by val. It is a lot safer and makes debugging easier. As
strings can take a lot of processing to copy if you have a performance issue
you may want to use byRef if you need to pass a lot of strings...

HTH

"Tom Ogilvy" wrote:

It is defined in the help for SUB

Sum Main()
Dim dbllLen as double, dblWidth as double
dblLen = 6
dblWidth = 8
SubComputeArea dblLen, dblWidth
End Sub

Sub SubComputeArea(Length, TheWidth)
Dim Area As Double ' Declare local variable.
If Length = 0 Or TheWidth = 0 Then
' If either argument = 0.
Exit Sub ' Exit Sub immediately.
End If
Area = Length * TheWidth ' Calculate area of rectangle.
Debug.Print Area ' Print Area to Debug window.
End Sub

If you know you are going to pass variables defined as double you can do

Sub SubComputeArea(Length as double, TheWidth as double)

Length and TheWidth are declared along with the Sub in the sub declaration
(the line above)

They are place holders for the variables actually passed to the sub.

by default they are passes a references so if the sub does anything to the
passed variables the values held by those variables is changed (you can
explicitly do

Sub SubComputeArea(byRef Length as double, byRef TheWidth as double)

If you use ByVal, then the value held be the variables are passed and the
function uses the placeholder variables (so to speak) to hold the passed
values and those placeholder/dummy variables are manipulated in teh sub.
Unlike the byRef variables, the original variable values are not affected by
actions performed in the sub.

--
Regards,
Tom Ogilvy


"Wally Steadman" wrote in message
...
Was reading the Excel Help on the Sub Statement and this is the example
that
is shown:
' Sub procedure definition.
' Sub procedure with two arguments.
Sub SubComputeArea(Length, TheWidth)
Dim Area As Double ' Declare local variable.
If Length = 0 Or TheWidth = 0 Then
' If either argument = 0.
Exit Sub ' Exit Sub immediately.
End If
Area = Length * TheWidth ' Calculate area of rectangle.
Debug.Print Area ' Print Area to Debug window.
End Sub

I notice that the there is Lenght and TheWidth in the brackets after the
sub
name. Am I correct in assuming that these have to be given values
somewhere? I notice in the sub routine they are not defined so I am
assuming they are definned elsewhere. I am trying to learn about the
arguments that can go in that set of brackets after the sub name to
further
my knowledge. I see things like Sub Name(ByVal etc...) and was trying to
figure out the whens and whys of using that and where is that stuff
defined
as I cannot find it in the help when I do a search for ByVal etc....

Thanks in Advance and have a Happy New Year everyone

Wally Steadman